The present paper discusses the designing of metallic earth-air tunnel system taking under consideration all the variables like cooling load, heating load of the classroom, optimum underground temperature, and weight of the soil acting on the underground duct. Duct is of Zigzag pattern and its cross-section is of square shape. The zigzag pattern resulted in less area occupied and shorter length of the duct required for proper air-conditioning effect. Part of the duct leading to the classroom is insulated in order to stop the temperature change of the conditioned air after coming in contact with atmospheric conditions. The results showed a 13oC reduction in temperature during summers. Heating effect in winters was relatively less, with just 5oC increase in temperature. Keywords: Ground Temperature Estimation, Metallic Duct, Heating and cooling Load, Pressure Drop in the Duct, Year Average C.O.P.
